The colors in images from a digital camera or camcorder or displayed on a television screen or the monitor display of a personal computer frequently exhibit differences from image to image due to a variety of reasons. In order to maintain constant color appearance from image to image, a technique referred to as white balancing is often employed. Using this technique, the white in an imaged scene is used as a reference, allowing the entire scene to be color-adjusted based on that white.
Conventional white balancing of digital images is provided through both manual and automatic means. For manual white balancing, the imaging device is typically aimed at a reference surface that is presumed to be white under white illumination. For automatic white balancing, an assumption is generally made that a white object exists within the imaged scene and presumably the white object corresponds to the brightest spot in the image. The white balancing is then performed using that assumed white object as a reference. However, when a white object is not actually within the imaged scene or the brightest spot does not belong to a referenced white surface, this technique may lead to incorrectly adjusted images.